Field of the Invention
Embodiments of the present invention generally relate to methods for forming semiconductor devices. More particularly, embodiments of the present invention generally relate to methods for forming an interconnection structure using nickel silicide for semiconductor applications.
Description of the Related Art
Integrated circuits have evolved into complex devices that can include millions of components (e.g., transistors, capacitors and resistors) on a single chip. The evolution of chip designs continually requires faster circuitry and greater circuit densities. The demand for greater circuit densities necessitates a reduction in the dimensions of the integrated circuit components.
As the dimensions of the integrated circuit components are reduced (e.g., sub-micron dimensions), the materials used to fabricate such components contribute to the electrical performance of such components. As the feature widths decrease, the device current typically remains constant or increases, which results in an increased current density for such features. Higher device densities, faster operating frequencies, and larger die sizes have created a need for a metal with lower resistivity than traditional aluminum to be used in interconnect structures. Copper materials with lower resistivity have been used for decades for its high conductivity. However, as discussed, small size effect may also result in increased resistivity of copper as line widths shrink below around 50 nm and approach the mean free path of electrons in copper (39 nm). The resistivity increase is caused by electron scattering at the surface of the line and at grain boundaries.
Conventional copper wire may also cause electromigration when current density exceeds certain level. Electromigration defects threaten the reliability of nanometer-size copper interconnects. Electromigration causes internal and external cavities that lead to wire failure. For example, electromigration may lead to increased electrical resistance or even an open circuit if a sufficiently large void forms within the copper interconnection.
In order to overcome these drawbacks for next generation small dimension technologies, many new materials, such as carbon nanotubes and the like, have been researched for the possibilities to replace copper with better electrical conductive properties, lower electrical resistance as well as higher device speed. However, there remain several challenges in integrating new materials into an interconnection structure with desired electrical properties, high mechanical strength and integration capability.
Therefore, there is a need for a suitable material for metal interconnection for semiconductor interconnection manufacturing process.